19. When an equal volume of sugar and water are mixed completely, the combined volume is less than the sum of the volumes of the unmixed sugar and water. What is the reason for this observation?

a. The water molecules would fit in the spaces between the sugar molecules.

b. A small amount of water evaporated while sugar and water were being mixed.

c. The molecules of water are in constant motion which makes them evaporate easily.

d. The molecules of sugar are doser to each other making them easier to come even closer to each other.​